I think that a big cause of political instability can be when people are greatly divided in a country or region. If half the people want one type of government and half want another this can cause big problems. There will often be minority governments. Of course, one person will always get elected, but half the population will be unhappy. They will protest so many of the decisions that are made. They can even cause a reelection to happen. If there actually is a reelection and they win, then the other half of the population can be unhappy. I don't know what it is that can cause such great divides, but something I think it's done on purpose. It's all a big show. Companies throw around big money behind the scenes.  They want people to be divided and focus more on that than what the real problems their country is facing.